BMW Luxury Touring Community banner
1 - 16 of 16 Posts

·
Registered
Joined
·
215 Posts
Discussion Starter · #1 ·
I just figured the other thread team it's course.
I don't have gs911 so I can't park the stepper motors (whatever they are)
My question is can a decent tbs be done without gs9/11
 

·
Registered
Joined
·
73 Posts
twincruise said:
Can a decent tbs be done without doing anything to the stepper motors?
I'm new to BMWs ... so beware ...

I believe the stepper motors are for idle only. When you twist your throttle to anything above idle RPM the cables pull the throttle linkage off of the stepper motors and then they become insignificant. But you can adjust the cables for an even idle vacuum. I wouldn't worry too much if there is a little imbalance at idle, it's no biggie. What you want is close balance at 2000 rpm.

I think I remember reading somewhere that when you turn the ignition ON you should wait 10 to 15 seconds for the red triangle and then the yellow triangle lights to go out before engaging the starter. I THINK someone said this has to do with the stepper motors getting in sync with each other. Can someone more knowledgeable than me give some input on this as it is related to the OP's question.

Norm
 

·
Registered
Joined
·
2,128 Posts
You are suppose to wait for the red triangle to extinguish before hitting the starter, part of the throttlebody to computer sync thing. I thought the dealer told me to wait for the amber to go out as well but folks here told me I didn't need to wait on the amber.

I would not think the stepper motors would come into play once the bike is off idle and since the TBS is done at 2k rpm, I don't see a problem.

Now I see the TBS coming up a lot but frankly I have 22k on my 11 month old RT and have yet to sync the throttle bodies. I BELIEVE folks are taking this maintenance schedule thing WAY TOO FAR. The old saying "if it ain't broke don't fix it" comes to mind. Check your valves, change your oils/fluids and ride it so long as it isn't acting up. I'll check the TBS over the winter months when riding isn't possible.
 

·
Registered
The Villages, FL
Joined
·
2,601 Posts
I recently checked my valves at 18k and did make some minor adjustments. For the throttle sync, I purchased the Twinmax unit. My throttlebody did not need syncing at this time.
 

·
Registered
Joined
·
215 Posts
Discussion Starter · #7 ·
thanks for the info
I'm with Teach as far 'if it don't need it don't do it'
But for the last two months or so I've noticed more vibration more like a tingle mostly on right grip. I've changed gloves, switched to different gas station, suspected tires (I have pilot 3 with 3500miles on them)

So i figured since I'm coming up on 12000 miles I'll do valves and tbs and hope that gets rid of some vibration

I appreciate all the info I've gotten here it really helps
 

·
Registered
Joined
·
2,128 Posts
twincruise, I'm gonna bet you've got a valve out of spec and thats your vibe issue. I could hear my sloppy exhaust valves on the right side, and could feel the vibe's through the bars. I wasn't expecting the valve adjustment to cure anything but the ticking, but it smoothed the motor right out.
If you are gonna pull the plastic you may as well do the tbs at the same time ;)

Since the tbs topic has come up again I saw something on the aerostich site that may make the job a little easier. They sell a throttle lock/cruise control clip for $20 if I recall properly. This is the perfect gadget to hold the throttle steady at 2k rpm. Just sayin...

Yep, found it. Its called the "Go Cruise" and the Aerostich #1757, $20.00
 

·
Registered
Joined
·
16 Posts
did the valves and TB sync about a month ago.

always felt like the engine didn't like to rev above 4 or 5K. it would do it, but it seemed labored.

The valves were a few thou's off, but the TB was noticeably unbalanced. Got everything as perfect as I could, and now the engine revs very freely up to redline, and smoother.

This bike is very easy to work on. The hardest part seems to be taking the spark plug out, finding TDC, and taking the plastics off. The online how-tos are excellent. Next time I do it, it will probably take an hour or so. half of that spent with the plastics.

The stepper motors weren't an issue.
 

·
Premium Member
Joined
·
2,697 Posts
I've been away from the board on a trip for a week or so...

The answer is... You do not have to worry about the steppers.

Doing a TBS with any tool such as a Twinmax or even the home-made manometer types.... just bring the RPM slightly off idle then do the TBS. That is the RPM range that gives the greatest variation, if there is any, between one side and the other.

My reference on this is Paul Glaves who writes the technical/maintenance section of the BMW Owner's News and who is available to those to are BMW MOA members on the MOA Forum.
 

·
Registered
Joined
·
175 Posts
Teach said:
{snip}...I saw something on the aerostich site that may make the job a little easier. They sell a throttle lock/cruise control clip for $20 if I recall properly. This is the perfect gadget to hold the throttle steady at 2k ...{snip}
If you have a small pair of vice-grip pliers, they do an admiral job as well.
 

·
Registered
Joined
·
2,047 Posts
Just to clarify, you don't need to lock the throttle to do a TB sync. Trial and error works just fine (rev it up, note the gauge reading, shut down, adjust, repeat until you get it right).

Just be sure your valves are adjusted first (cold engine) and that when you do the TB sync the engine is thoroughly warmed up.

JayJay
 

·
Premium Member
Joined
·
2,697 Posts
JayJay said:
you don't need to lock the throttle to do a TB sync. Trial and error works just fine (rev it up, note the gauge reading, shut down, adjust, repeat until you get it right).

Just be sure your valves are adjusted first (cold engine) and that when you do the TB sync the engine is thoroughly warmed up.

JayJay
plus 1 on what he said...
 

·
Registered
Joined
·
175 Posts
IIRC, the RepROM indicates an rpm level of about 1750-1800 as being the preferred point for synching the TBs off-idle. A low-rpm off-idle level such as this tends to be the most sensitive range for TB synching. Thus, if you can get the TBs synched there, you'll be good to go at higher rpms.
 
1 - 16 of 16 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top